Questionable noise on 3.0 lt SC

anaphe · 04-07-2005, 11:28 AM

So I picked up my new p-car today. I bought the car in California, drove it to BC. Had a well known interior shop do some work and now I picked it up from the train today in Calgary

On acceleration at about 4000 rpms there is an audible "farting" sound - like air out of a baloon or whoopie cusion, on decel the car seems to be the same. The sound also seemed to go away as the car warmed up and I am not sure but there appears to be a bit less power but still feels solid.

The oil was down about 1.5 litres courtesy of the shop owner driving it around

!

Any ideas? Where do I start. Exhaust?

It is going in for an inspection for registration here and my mechanic does 95% of business on porsches so he will probably have an idea but I wanted to get an idea first$$$.

Paulporsche · 04-07-2005, 11:47 AM

Exhaust could be a cause.

However, I am thinking the mixture in CA could be set a little lean for your temps now in Calgary, especially when the engine is cold. Your WUR could be out of spec, giving you a too lean condition when cold, or it might just be the mixture setting. Try richening it a little (about 1/8 turn @ a time) and see what happens.

Don't worry about the oil level being a little low for a short time. Is it filled correctly now?

Superman · 04-07-2005, 11:53 AM

Did you have a PPI done, and did the PPI include counting head stud nuts? Our cars have a nasty habit of breaking head studs, which allows the cylinder head to clap against the cylinder top, and this kind of noise can be one of the symptoms. Under the valve covers, there should be 24 nuts. Your mechanic will know exactly what I'm talking about.

MotoSook · 04-07-2005, 11:58 AM

Good call Jim.

MAS · MAS's Garage

At the risk of telling you something you already may know... you cannot check the oil level in the "normal" non-Porsche car way. The oil has to be checked with the car running and with the car at operating temperature (which is around 175F or about 80C). If you check the oil when the car is cold and not running, then the dip stick level will be at or below the LOW mark... which is about 1 1/2 litres below the FULL mark.

The chances are that you do not need any more oil.

(Incidentally, overfilling with oil is a very common mistake made by new 911 owners)

Good luck with the new car

-MAS

anaphe · 04-07-2005, 12:06 PM

Would this go away as the car warmed up and the case and heads expanded? I will check this week. Where does the broken stud go? Is it bouncing about in the valve train?

anaphe · 04-07-2005, 12:07 PM

Thanks MAS this is not my first PCar, Tank gauge indicated that oil level was low, it was check on level surface when warm at idle......down close to 2.ltres

Superman · 04-07-2005, 01:06 PM

The noise would subside somewhat after warmup, for the reason you mentioned. The other end of the head studs are "Loctited" into the case, so that part won't go anywhere. the top part, with the nut, can fall into the area under the valve cover. I have not heard of that part creating more damage. it just rattles in there until someone removes it. Some say driving with one broken stud is okay (there are four per cylinder). I drove many miles this way. Eventually though, we fix them and it requires removing heads and cylinders. So, we do engine rebuild work while it's apart. Just look into it. Maybe that's not the case with your engine. If it is, it's not the end of the world.